The present invention is directed to a particle bombardment system for delivering substances into living cells and tissues and more specifically, to an apparatus for accelerating microprojectiles carrying these substances into a vacuum chamber containing the cells and tissues to be penetrated by the substances without contamination or lethal damage of the living cells and tissues by the specific means used to accelerate the microprojectiles.
The named inventors of the present application are also the named inventors of copending U.S. patent application Ser. No. 877,619 filed Jun. 23, 1986, now abandoned, which is a Continuation-in-Part of application Ser. No. 670,771 filed Nov. 13, 1984, now U.S. Pat. No. 4,945,050, which is directed to a "Method for Transporting Substances Into Living Cells and Tissues and Apparatus Therefor". The biolistic process disclosed in these applications is a new and unique method for delivering substances into living cells and tissues.
Needleless hypodermic injectors are old and well known in the art for introducing substances into tissues but not into cells. The U.S. Patent to Clark et al. (U.S. Pat. No. 3,853,125) discloses such a disposable needleless injector which includes a medicament containing ampule, a container of pressurized gas and a connection operatively coupling the gas to the ampule to pressurize the medicament for discharge. The ampule includes at least one rigid end wall which is provided with an opening therein which serves as a discharge orifice through which the pressurized medicament is discharged in the form of a high pressure injection stream. The opposite end of the ampule is configured to permit the medicament to be rapidly pressurized by the gas.
The U.S. patent to Schwebel et al. (U.S. Pat. No. 4,124,024) is also directed to a disposable hypodermic injection ampule for performing needleless percutaneous injections. A propellant charge in one end of the device is exploded by means of a firing pin and the explosive gases drive a plunger to pressurize the fluid injectant and force it outwardly of the device through a discharge orifice.
The U.S. patent to Tsujino (U.S. Pat. No. 3,515,130) is directed to a jet-injection hypodermic device which consists essentially of a hydraulically operated injector, hydraulic pressure means connected to and supplying hydraulic pressure to the injector and hand operated control means to control the hydraulic pressure. The injector comprises an injector head containing a piston pump for drawing in injection liquid through an inlet and ejecting the liquid through a fine ejection orifice. The hydraulic piston is driven in one direction for ejecting the injection fluid by hydraulic pressure and in the opposite direction for drawing in injection liquid by a return spring.